Community Forums

ARFFMAN · 04-06-2014, 07:29 PM

I have a 1994 MH on a F53 chassis. I took it on a road trip and about 1.5 hours into trip it started to lose power and if I gave it gas it would back fire. I saw a whisper of smoke come from dash. and speedometer went to zero and odometer went out. After sitting for about 30 minutes drove off for about 30 more minutes and same scenario. ( this time the speed speedometer or odometer didn't work)
I have recently did a complete tune up, new plugs ,wires, rotor cap. New fuel system, turbo style pump, filters etc. while fuel tank was removed cleaned and sealed tank and flushed fuel lines I'm leaving camp site in 4 days. and try to get back home. The engine only has 42,000 miles on it, and the above parts have less than 300 miles on them. I bought a fuel filter today and will install it tomorrow. (don't think this will help) I'm lost, HELP!

Full.Monte · 04-07-2014, 10:57 AM

Wow! The only thing I can think of is "Never assume you have only one problem". The original problems sound like you at least had a fuel blockage...probably due to a plugged up fuel filter. On the dash speedo and odo problem, I would check the fuses controlling the dash.

garykk · 04-07-2014, 11:22 AM

I agree, sounds like two separate problems. Ist one sounds like a fuel shortage, could be filter, could be a collapsing fuel line if any part of it is rubber, could be a problem in the tank especially if you had it down.
The puff of smoke sure sounds like a wire shorted under the dash...

subford · 04-07-2014, 07:07 PM

Fuse #4 a 15amp and fuse #5 a 20 amp fuse are for the Speedometer/Odometer (PSOM).

Sounds like you may have a bad Ignition Switch or the plug that plugs into it. Fuse #4 is feed from the Ignition switch and of course the Ignition switch also controls the PCM Power relay that sends power to the coil of the fuel pump relay.

Does the Warning Chime and the volt meter work when the key is turned on?
They are also powered by fuse #4.

ARFFMAN · 04-08-2014, 07:38 PM

I'll check out the fuses and ignition switch in morning. Does the ignition switch control speedometer too? When you refer fuse # 4, is the fuse located under dash near hood release of under hood, drivers side? Thanks for your help!

ARFFMAN · 04-08-2014, 07:40 PM

Not sure what you mean, Warning Chime

subford · 04-09-2014, 06:46 AM

Quote:

Originally Posted by ARFFMAN

I'll check out the fuses and ignition switch in morning. Does the ignition switch control speedometer too? When you refer fuse # 4, is the fuse located under dash near hood release of under hood, drivers side? Thanks for your help!

Yes the Ignition switch powers a bar in the fuse panel located under dash near hood release. This bar powers 5 fuses, one of the fuses sends power to the PSOM as described below.

This fuse is called fuse #4 in the Ford EVTM but its location in the EVTM dose not match the large fold out print for the 1994 F53 from Ford.

This fuse then sends power over a red wire with a yellow stripe (wire #640) to the gray plug on the back of the cluster (pin #13). At the gray cluster plug pin #13 the red wire with a yellow stripe is joined with another red wire with a yellow stripe and goes to the brown plug on the cluster at pin #11. At the cluster brown plug pin #11 the red wire with a yellow stripe is joined with another wire, a wire #489 that is a pink wire with a black stripe and this wire goes to the PSOM plug pin #3 to turn on the PSOM so the PSOM can drive the stepper motor for the speedometer head and also the odometer.

Fuse panel EVTM:

Fuse panel large fold out:

/

ARFFMAN · 04-09-2014, 02:53 PM

Change out fuel filter today. Didn't appear to be blogged. Will be leaving site tomorrow. Keeping my fingers crossed. One thing that puzzles me is I found three wires (2 black with white strip and 1 black) when I bought MH they were not connected to battery( has a battery eye on end) all 3 wires come from a plug (Possible negative side of battery) When I plug in the male end I get a clicking from fuel pump relay and also somewhere near front of fuel rail. As I stated above. On end appears to connect to neg. side of ign. battery to a male 3 way plug that goes into wiring harness. Also it doesn't matter if I have neg. side of battery connected or not, I still get a clicking sound from fuel pump relay and somewhere near fuel rail. I'll send pictures if I can figure out how.

ARFFMAN · 04-09-2014, 03:00 PM

Checked all fuses and #4 and I had power and no fuses blown.When I get back home I guess I'll start tracing down the wiring from # 4. I hope the smoke was something that won't come back at least till I get home.

subford · 04-09-2014, 05:32 PM

Here is where the wire should go:

/

ARFFMAN · 04-09-2014, 06:26 PM

If I'm reading the above right, then the 3 wires I discovered should go to ground to frame.
If I unplug the plug then engine won't start. What do the 2 black w/white strip and 1 black wire do? The wire diagram only shows they 3 wires but is cut off at top on where they go. I have a ford 1994 powertrain/drivetrain manual and a Ford chassis manual but not sure where to look.

subford · 04-09-2014, 09:52 PM

Quote:

Originally Posted by ARFFMAN

If I'm reading the above right, then the 3 wires I discovered should go to ground to frame.

No they go to the NEG post of the battery and another large wire goes from the NEG post of the battery to the frame.

Quote:

Originally Posted by ARFFMAN

If I unplug the plug then engine won't start.

True, with the plug unplugged you have no ground to the computer or any other engine circuit.

Quote:

Originally Posted by ARFFMAN

What do the 2 black w/white strip and 1 black wire do?

The black wire goes to a lot of circuit ground points & pin #6 of the PCM computer.
One of the black w/white strip wires go to pin 40 of the PCM Computer.
One of the black w/white strip wires go to pin 60 of the PCM Computer.
Pin 40 & pin 60 of the PCM Computer are tied together inside the PCM Computer. They are used to ground all the relays, solenoids to run the engine and operate the transmission.
Pin #20 of the PCM computer is grounded to the dash near the PCM computer.

Quote:

Originally Posted by ARFFMAN

The wire diagram only shows they 3 wires but is cut off at top on where they go. I have a ford 1994 powertrain/drivetrain manual and a Ford chassis manual but not sure where to look.

Not sure what manual you are talking of. Is it the EVTM by Ford or the large shop manuals by Ford?
Nether goes into the detail that I posted above.

Battery Grounds:

/

subford · 04-10-2014, 07:09 AM

I up dated the image above that I deleted to show where the ground wires go.

/

ARFFMAN · 04-10-2014, 05:07 PM

Well I made it back home, only had to shut down motor twice. The trip was mostly down hill or level grade (S.C. Low Country) I figured out that if I cruised at about 1800 - 2000 RPMs, everything was good. If I needed more power(gas pedal) or climbing a grade I would loose power and to regain fairly normal power I would have to pull over and shut down for only a few minutes. It acted like something wasn't communicating with transmission The transmission would shift through all it's gears but no power when it did.